The mystery involves the murders of the two producers of a play. The solution to the first murder, and the motive of the killer in the second murder are plausible, but the solution provided for the second murder I think is ridiculous. I mostly didn't care much, instead enjoying the interplay between Denny and Brent.
I downloaded the 767MB MPEG2 file. I often had trouble understanding dialog in the first half or so of the movie. Voices were often low or the actors spoke fast, and noise was a problem, but it improved. Video and audio quality are otherwise fine.